Security System Questions

Would a security system sound if someone broke a window and gained access to a house that way? Or is it just for the door? Also, anybody with law enforcement background, please PM, I'm writing a novel which deals with a criminal and want my facts straight -- there'll be rep in it for you.

Would a security system sound if someone broke a window and gained access to a house that way? Or is it just for the door? Also, anybody with law enforcement background, please PM, I'm writing a novel which deals with a criminal and want my facts straight -- there'll be rep in it for you.

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You can have both. There are security systems that offer glass break sensors and door sensors. It depends on what you purchase when you get into the system, but both kinds of sensors exist.

Yeah, could be either. Systems are often installed around windows. Often, they have a sensor with two pieces - one on the window and one of the frame. When the window is opened, it sends a signal to the alarm. If you're looking more at glass breaking, they have sensors designed to detect the sound of breaking glass, and when they hear it they send a signal to the alarm. All of these can be used in conjunction.

Hm, okay, thanks. Does it seem too coincidental if my MC breaks into a house via the window and the alarm doesn't go off?

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No. A lot of people don't get those window break sensors in their homes. I see them used more by businesses. Breaking the window wouldn't trip the most commonly-used window sensors, which are used to sense whether the window is physically opened. People do use the glass-break sensors in their home, but it certainly wouldn't be unusual for a home with a security system not to have them. It's probably the more common option, in fact.

There are all kinds of security systems. Perimeter alarms protect entry points, such as doors, windows, and skylights. There are also area alarms such as ultrasonic or optical motion sensors. Thermal sensors can register body heat, but they can also assist in fire detection.

In addition to alarms, security systems can also switch on surveillance cameras and recorder, so even if no immediate alert is sounded, a records can be available for review.
The protected space is often divided into zones, so intrusions can be tracked by more than an overall alarm/no-alarm condition.

I haven't noticed lately, but I used to see a lot of windows with a thin conductive strip or tape on the glass, so if the glass was broken it would open a circuit.

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It's rather low-tech, and fairy easy to defeat. You can usually cut an opening in the glass without breaking the strip. Sometimes you can bridge the contacts so that even if the strip is broken, the alarm doesn't sound.

The most common type of sensor used in domestic security systems is a motion detector - most houses with an alarm would just have one, in the main hallway, and maybe sensors on the ground floor doors.

So, if your character is just breaking in to a standard house, going through the window, and avoiding the hallway, he may well avoid setting the alarm off. The more security-conscious the home owner is, though, the more sensors there are likely to be (upstairs hallway motion detector, ground floor windows would be the next ones generally added.) But still, in most homes even with reasonable electronic security, if you broke directly in through an upstairs window to access that room and didn't go any beyond the room you entered, the chances are there wouldn't be any sensors covering it.

I think the most common used sensors are reed switch or door sensor. These sensors are cheap but 100% reliable. For the security system, there are wide range of different kinds of intrusion sensors for selection, which including magnetic contact (reed switch), PIR motion sensor, Dual-tech motion sensor, glass break sensor, vibration sensor, perimeter beam sensor...etc. Each of sensor with its advantages and disadvantages, suitable for different application or installation environment. Typically, when the sensor is triggered, it will send the signal to alarm panel, alarm panel will trigger the alarm immediately.

Would a security system sound if someone broke a window and gained access to a house that way? Or is it just for the door? Also, anybody with law enforcement background, please PM, I'm writing a novel which deals with a criminal and want my facts straight -- there'll be rep in it for you.

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depends on how it's set up... windows are frequently included in the system and if broken can set off the alarm... doors are always wired and motion detectors are also frequently included...

i had such a system when i lived in an upscale part of las vegas, so am speaking from first-hand knowledge...

It's rather low-tech, and fairy easy to defeat. You can usually cut an opening in the glass without breaking the strip. Sometimes you can bridge the contacts so that even if the strip is broken, the alarm doesn't sound.

Vibration sensors mounted on the glass are much harder to defeat.

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This could be quite a good option for the MC then. If he/she breaks into houses fairly regularly, or does dabble in a bit of petty theft, this could be used to show it and having to defeat a small circuit is still more exciting than "The MC broke the window and clambered in"

This could be quite a good option for the MC then. If he/she breaks into houses fairly regularly, or does dabble in a bit of petty theft, this could be used to show it and having to defeat a small circuit is still more exciting than "The MC broke the window and clambered in"

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Or maybe "MC smiled as he saw the sensor strip. Easiest things in the world to beat, these things. A small rod would bridge the circuit and render it useless." to show off his expertise?

For someone who just practices some petty theft, but does have a bit of experience, the most common thing would be to look for a diffrent point of entry if they found a sensor. For example, if s/he sees a sensor strip on a window on the groudn floor, s/he'd probably try to enter an upstairs window instead (via a garage roof or whatever) to AVOID the sensor. Much easier (and thus less risky) than trying to bypass a sensor.

For someone who just practices some petty theft, but does have a bit of experience, the most common thing would be to look for a diffrent point of entry if they found a sensor. For example, if s/he sees a sensor strip on a window on the groudn floor, s/he'd probably try to enter an upstairs window instead (via a garage roof or whatever) to AVOID the sensor. Much easier (and thus less risky) than trying to bypass a sensor.

If they get past the door and window sensors, you're still going to have to deal with motion detectors. Pretty much every home alarm system has motion detectors as well, and they are sensitive little buggers. The question I have for you is; what is it that you want your MC to do? Do you WANT him/her to get around an alarm, or not? If you do... make up some kind of invention that would disable the system, regardless of how sophisticated it is. If not, then, well-- that's easy.